1. Field of the Invention
The invention relates to a steering system including a magnetic detection device.
2. Description of the Related Art
A conventional steering system includes, as a magnetic detection device, a torque detection device that detects a steering torque applied to a steering wheel. The torque detection device has a configuration in which a steering shaft is inserted in the torque detection device. The torque detection device includes a magnetic detection portion that detects magnetism, and a magnetic shield that restrains earth's magnetism from collecting the magnetic detection portion, by surrounding an outside of the magnetic detection portion. As an example of such a steering system, there is a steering system described in Japanese Patent Application Publication No. 2011-122943 (JP2011-122943 A).
In the conventional steering system, the steering shaft is inserted in the torque detection device, and therefore, it is difficult for the magnetic shield to cover the magnetic detection portion in an axial direction of the steering shaft. Therefore, the earth's magnetism tray affect the magnetic detection portion via the steering shaft. Accordingly, even when the same steering torque is applied to the steering wheel, the torque detection device may detect the steering torque as a different torque. A similar phenomenon also occurs in a magnetic detection device other than the torque detection device, for example, a steering angle detection device that detects a steering angle of the steering wheel.